NASA Leads Study of Unprecedented Arctic Ozone Loss

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 PHONE 818-354-5011
http://www.jpl.nasa.gov

Alan Buis 818-354-0474
Jet Propulsion Laboratory, Pasadena, Calif.
Alan.buis@jpl.nasa.gov

Steve Cole 202-358-0918
Headquarters, Washington
Stephen.e.cole@nasa.gov

News release: 2011-308 Oct. 2, 2011

NASA Leads Study of Unprecedented Arctic Ozone Loss

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2011-308&cid=release_2011-308

PASADENA, Calif. – A NASA-led study has documented an unprecedented depletion of Earth's
protective ozone layer above the Arctic last winter and spring caused by an unusually prolonged
period of extremely low temperatures in the stratosphere.

The study, published online Sunday, Oct. 2, in the journal Nature, finds the amount of ozone
destroyed in the Arctic in 2011 was comparable to that seen in some years in the Antarctic, where an
ozone "hole" has formed each spring since the mid-1980s. The stratospheric ozone layer, extending
from about 10 to 20 miles (15 to 35 kilometers) above the surface, protects life on Earth from the
sun's harmful ultraviolet rays.

The Antarctic ozone hole forms when extremely cold conditions, common in the winter Antarctic
stratosphere, trigger reactions that convert atmospheric chlorine from human-produced chemicals into
forms that destroy ozone. The same ozone-loss processes occur each winter in the Arctic. However,
the generally warmer stratospheric conditions there limit the area affected and the time frame during
which the chemical reactions occur, resulting in far less ozone loss in most years in the Arctic than in
the Antarctic.

To investigate the 2011 Arctic ozone loss, scientists from 19 institutions in nine countries (United
States, Germany, The Netherlands, Canada, Russia, Finland, Denmark, Japan and Spain) analyzed a
comprehensive set of measurements. These included daily global observations of trace gases and
clouds from NASA's Aura and CALIPSO spacecraft; ozone measured by instrumented balloons;
meteorological data and atmospheric models. The scientists found that at some altitudes, the cold
period in the Arctic lasted more than 30 days longer in 2011 than in any previously studied Arctic
winter, leading to the unprecedented ozone loss. Further studies are needed to determine what factors
caused the cold period to last so long.

"Day-to-day temperatures in the 2010-11 Arctic winter did not reach lower values than in previous
cold Arctic winters," said lead author Gloria Manney of NASA's Jet Propulsion Laboratory in
Pasadena, Calif., and the New Mexico Institute of Mining and Technology in Socorro. "The
difference from previous winters is that temperatures were low enough to produce ozone-destroying
forms of chlorine for a much longer time. This implies that if winter Arctic stratospheric temperatures
drop just slightly in the future, for example as a result of climate change, then severe Arctic ozone
loss may occur more frequently."

The 2011 Arctic ozone loss occurred over an area considerably smaller than that of the Antarctic
ozone holes. This is because the Arctic polar vortex, a persistent large-scale cyclone within which the
ozone loss takes place, was about 40 percent smaller than a typical Antarctic vortex. While smaller
and shorter-lived than its Antarctic counterpart, the Arctic polar vortex is more mobile, often moving
over densely populated northern regions. Decreases in overhead ozone lead to increases in surface
ultraviolet radiation, which are known to have adverse effects on humans and other life forms.

Although the total amount of Arctic ozone measured was much more than twice that typically seen in
an Antarctic spring, the amount destroyed was comparable to that in some previous Antarctic ozone
holes. This is because ozone levels at the beginning of Arctic winter are typically much greater than
those at the beginning of Antarctic winter.

Manney said that without the 1989 Montreal Protocol, an international treaty limiting production of
ozone-depleting substances, chlorine levels already would be so high that an Arctic ozone hole would
form every spring. The long atmospheric lifetimes of ozone-depleting chemicals already in the
atmosphere mean that Antarctic ozone holes, and the possibility of future severe Arctic ozone loss,
will continue for decades.

"Our ability to quantify polar ozone loss and associated processes will be reduced in the future when
NASA's Aura and CALIPSO spacecraft, whose trace gas and cloud measurements were central to
this study, reach the end of their operational lifetimes," Manney said. "It is imperative that this
capability be maintained if we are to reliably predict future ozone loss in a changing climate."

Other institutions participating in the study included Alfred Wegener Institute for Polar and Marine
Research, Potsdam, Germany; NASA Langley Research Center, Hampton, Va.; Royal Netherlands
Meteorological Institute, De Bilt, The Netherlands; Delft University of Technology, 2600 GA Delft,
The Netherlands; Science Systems and Applications, Inc., Greenbelt, Md., and Hampton, Va.;
Science and Technology Corporation, Lanham, Md.; Environment Canada, Toronto, Ontario,
Canada; Central Aerological Observatory, Russia; NOAA Earth System Research Laboratory,
Boulder, Colo.; Arctic Research Center, Finnish Meteorological Institute, Finland; Danish Climate
Center, Danish Meteorological Institute, Denmark; Eindhoven University of Technology, Eindhoven,
The Netherlands; Arctic and Antarctic Research Institute, St. Petersburg, Russia; National Institute
for Environmental Studies, Japan; National Institute for Aerospace Technology, Spain; and
University of Toronto, Ontario, Canada.

For more information on NASA's Aura mission, visit: http://www.nasa.gov/aura . For more
information on NASA's CALIPSO mission, visit: http://www.nasa.gov/calipso .

JPL is managed for NASA by the California Institute of Technology in Pasadena.

-end-

To remove yourself from this mailing, please go to http://www.kintera.org/TR.asp?a=mhKOJWOAI8LMIbI&s=ddKOIMOlH9IALLPrFnF&m=dpLNJTMzGfKMK7K

To remove yourself from all mailings from NASA Jet Propulsion Laboratory, please go to http://www.kintera.org/TR.asp?a=pkIUK5PMLbKTKlL&s=ddKOIMOlH9IALLPrFnF&m=dpLNJTMzGfKMK7K